code: def test_richclub_exception():
      with pytest.raises(nx.NetworkXNotImplemented):
          G = nx.DiGraph()
          nx.rich_club_coefficient(G)
  
file_path: networkx/networkx/algorithms/tests/test_richclub.py
imports: import pytest
  import networkx
label_desc: Use image node_id 7 for calling a global function with example usage: test_richclub_exception() without return types